WHAT CAUSES WATER POLLUTION
There
are many causes of Water Pollution-- some natural, some man-made.
Great strides have been made in cleaning up our fresh water
resources, but other problems persist, from massive hog farms
which poison rivers in the American southeast, to the unregulated
dumping of filth into India's Ganges River. Some of the major
agents of fresh water pollution are given below. This list is by no means
comprehensive.
Sewage
The run-off from human
settlements along the banks of rivers contain human, animal and industrial
waste. While the developed world can invest in and depend on sewage treatment
plants to treat waste before discharging it into rivers, rivers in less
developed countries run filthy, often serving as open sewers themselves. India
is among such countries and the most glaring example is the river Ganga, which
while flowing through one of the most densely populated areas on earth, absorbs
millions of gallons of raw human, animal and industrial waste every day. This
pollution increase the Biological Oxygen Demand and disrupt the aquatic
ecosystems. The water has high fecal coliform count and is a source of water
borne diseases like cholera and gastroenteritis.
Animal
waste
Cattle and pig rearing
activities generate enormous amount of nutrient-rich waste. This causes
accumulation of virulent pfiesteria toxin in water masses. This toxin killed the
fish in Neuse River of North Carolina by the hundreds of million. In humans,
this toxin is known to cause breathing problems and cognitive impairment.
"There are more pigs in North Carolina than people, and they are generating
more waste than all the people in California," says Kevin Madonna, an
official with Riverkeeper Inc. Unregulated dumping and seepage of hog waste into
rivers is a particularly dangerous form of pollution in the United States.
Fertilizers
and Pesticides
Most of the chemical fertilizers, herbicides and pesticides used in farming
eventually end up in rivers. Fertilizers are rich in Nitrogen and Phosphorus,
which causes a high Biological Oxygen Demand in the water. Severe depletion of
oxygen chokes the life out of water and ultimately only anaerobic life-forms
thrive. The area of the Gulf of
Mexico where the Mississippi flows into it has been declared a "dead
zone" because of agricultural pollution. Pesticides, on the other hand, are
long life toxins and can render water unfit for human or animal consumption.
Mercury
All
coal contains mercury, which is released into the atmosphere upon combustion of
coal. This mercury finds its way into rivers and lakes and even ground water.
Mercury while toxic to all is a serious health hazard for pregnant woman and
infants. According to the National Wildlife Federation, coal-burning power
plants in Ohio emit mercury into lakes, rivers and streams in Ohio and the Great
Lakes region. Societies generating power from thermal power plants are at a
great risk as compared to those depending on gas-turbines or hydroelectric
power.
